Regenerative Braking Control Strategy For Electric Vehicle Based On Dual Pedal Braking Intention Recognition

Electric vehicles have the advantages of high efficiency,zero emission,and independence on conventional energy,so it has become the main direction of the global automobile industry.However,the short driving range is the important problem of electric vehicles.Regenerative braking technology can significantly improve the driving range of electric vehicles by recovering excess kinetic energy during braking process.Therefore,the research on regenerative braking technology has great significance.In this paper,a regenerative braking control strategy for front-drive electric vehicles is proposed based on dual pedal braking intention recognition.The main research contents are as follows:(1)A braking intention recognition algorithm based on double pedal is designed.The time intervals among releasing the accelerator pedal,switching the brake pedal,and pressing the brake pedal were analyzed and processed to identify the driver’s braking intention.(2)A braking force variable ratio optimization algorithm of front and rear axles is designed based on the load and braking strength of the electric vehicle.According to the regulations of the Economic Commission of Europe(ECE),the ideal braking force distribution curve,the front and rear axle braking force relationship curve,and the constraint conditions of braking force distribution were determined,and then the optimized front and rear axle braking force distribution scheme was obtained by adjusting the constraints based on the position variation of the center of mass.Then more braking force is distributed to the front axle during the mild and moderate braking process to improve the regenerative braking energy recovery efficiency,and braking distance is reduced and braking safety and stability is improved during the emergency braking process.(3)A energy recovery strategy is developed based on the intention recognition and the brake force optimization distribution algorithm,and the motor and battery characteristics are considered.The front axle braking force is distributed secondary between the regenerative braking force and the mechanical braking force.And the proportion of the motor regenerative braking force in the total front axle braking force is increased so as to improve the regenerative braking energy recovery efficiency.(4)The proposed regenerative braking strategy has been verified.A regenerative braking control system model was established and simulated with the vehicle driving conditions under different loads,initial speeds,and braking intentions.The results verified the effectiveness and reasonability of the strategy.Main innovation points:(1)The speed and accuracy of the braking intention recognition algorithm was improved with the brake pedal data,accelerator pedal data and double pedal switching interval data.A multiple classifiers were designed with the data characteristics.The recognition speed can be improved by starting the classifier calculation before the data collection of the brake pedal data,and the recognition accuracy can be improved through integrated learning.(2)The braking force distribution curve was optimize based on the load and braking intention,and the energy recovery strategy was formulated with the characteristics of the motor and battery,and the braking safety and energy recovery efficiency was improved.